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Chris Lattner 7980fb9007 Add the ability to compute trip counts that are only controlled by constants
even if the loop is using expressions that we can't compute as a closed-form.
This allows us to calculate that this function always returns 55:

int test() {
  double X;
  int Count = 0;
  for (X = 100; X > 1; X = sqrt(X), ++Count)
    /*empty*/;
  return Count;
}

And allows us to compute trip counts for loops like:

        int h = 1;
         do h = 3 * h + 1; while (h <= 256);

(which occurs in bzip2), and for this function, which occurs after inlining
and other optimizations:

int popcount()
{
   int x = 666;
  int result = 0;
  while (x != 0) {
    result = result + (x & 0x1);
    x = x >> 1;
  }
  return result;
}

We still cannot compute the exit values of result or h in the two loops above,
which means we cannot delete the loop, but we are getting closer.  Being able to
compute a constant trip count for these two loops will allow us to unroll them
completely though.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13017 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-17 18:36:24 +00:00
autoconf Refactor external benchmark checking stuff into one hairy 2004-04-16 17:13:33 +00:00
docs Add idea about a disassembler. 2004-04-16 16:55:30 +00:00
examples/ModuleMaker Configure script for ModuleMaker. 2003-11-25 20:02:07 +00:00
include Switch to including <iostream> for compatibility with gcc-3.0.x (Debian). 2004-04-16 16:28:33 +00:00
lib Add the ability to compute trip counts that are only controlled by constants 2004-04-17 18:36:24 +00:00
projects If we're going to use tabs, use them consistently. Maybe doxygen will find the 2004-04-15 15:38:48 +00:00
runtime Fit comment into 80 cols. 2004-04-16 17:13:52 +00:00
test New testcase that Brian provided which crashes the inliner 2004-04-15 20:45:45 +00:00
tools Don't use invalid HTML in a doxygen comment. 2004-04-15 15:23:45 +00:00
utils The "best" of both worlds: readable C++ comments and valid HTML For doxygen. 2004-04-15 15:30:15 +00:00
.cvsignore
configure Regenerated using autoconf-2.57. 2004-04-16 17:13:44 +00:00
CREDITS.TXT Added Stacker to Reid Spencer's list of contributions. 2003-12-17 18:15:04 +00:00
LICENSE.TXT We actually don't have spiff anymore 2004-04-13 20:59:47 +00:00
llvm.spec RPM spec file for LLVM tools and libraries. 2004-02-10 03:57:51 +00:00
llvm.spec.in RPM spec file for LLVM tools and libraries. 2004-02-10 03:57:51 +00:00
Makefile As a part of the bootstrapping process, the top-level tools-only target 2004-04-16 15:57:02 +00:00
Makefile.common Added LLVM copyright notice. 2003-10-21 14:33:46 +00:00
Makefile.config.in Fix up a seriously outdated comment. 2004-03-10 17:37:50 +00:00
Makefile.rules Add support for 'install-bytecode' target, used for ONLY installing 2004-03-10 17:38:01 +00:00
README.txt Merged in RELEASE_1. 2003-10-27 18:02:06 +00:00

                       The LLVM Compiler Infrastructure
                           http://llvm.cs.uiuc.edu

Welcome to LLVM!
----------------
This file is intended to do four things:
(1) help you get started using LLVM;
(2) tell you how to get questions about LLVM answered;
(3) tell you where to find documentation for different kinds of questions; and
(4) tell you about three LLVM-related mailing lists.


Getting Started with LLVM
-------------------------

(1) For license information:
    llvm/LICENSE.txt

(2) Installing and compiling LLVM:
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(3) Learn about features and limitations of this release:
    llvm/docs/ReleaseNotes.html

(4) Learn how to write a pass within the LLVM system:
	llvm/docs/WritingAnLLVMPass.html

(5) Learn how to start a new development project using LLVM, where your
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    llvm/docs/Projects.html


Getting Help with LLVM
----------------------

(1) If you have questions or development problems not answered in the
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(3) We now use Bugzilla to track bugs, so you can check the status of
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LLVM Documentation
------------------

All the documents mentioned below except the design overview tech report
are included as part of the LLVM release (in llvm/docs/*):

LLVM Design Overview:
    LLVM : A Compilation Framework for Lifelong Program Analysis
    and Transformation:
        http://llvm.cs.uiuc.edu/pubs/2003-09-30-LifelongOptimizationTR.html

LLVM User Guides:

    Download and Installation Instructions:
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        llvm/docs/CommandGuide/index.html

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    LLVM Test Suite Guide:
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LLVM Programming Documentation:

    LLVM Programmers Manual:
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    Writing an LLVM Pass:
        llvm/docs/WritingAnLLVMPass.html

    Alias Analysis in LLVM:
        llvm/docs/AliasAnalysis.html

    Command Line Library:
        llvm/docs/CommandLine.html

    Coding Standards:
        llvm/docs/CodingStandards.html

Other LLVM Resources:

    Submitting a Bug:
        http://llvm.cs.uiuc.edu/docs/HowToSubmitABug.html

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        llvm/docs/OpenProjects.html

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